Coding my own aftermarket ECU

[antus]

also consider how to time dwell so the charge time is right before you fire the spark.

[AngelMarc]

And I don't know about a 3D table, but I might be able... daisy chain arrays. A 1D array pointed at by divided RPMtime in the middle full of various divisor values to scale RPMtime differently for pointing at VE table.

[AngelMarc]

understand whats happening, rather than writing it all for you

Literally what I've been doing as much as possible.

[antus]

3d means X and Y for location, Z for value, so you have 3D tables. 2D means 1 row or column only and a value.

[AngelMarc]

That is a perfect question for AI:

RPMtime = (2,500,000 / ( index - 1 )) * 600
Index = 1 + (2,500,000 * (RPMtime * 600))

https://chatgpt.com/share/6848bfe0-99f0 ... 51d98a254c

Thanks. Guess I was overthinking, wanted to use RPMtime directly instead of converting in arduino code. This should be fine.
Even inverts the index so lower number is slower.

[pman92]

Literally what I've been doing as much as possible.

Yes I can see but just thought I should mention it.
Sometimes I find myself going down a rabbit hole getting no where with something. Then some time later I actually think a bit more about what I was trying to do, and realise I was asking it the wrong questions. Not saying that's what your doing right now though

I've got wrapper functions that use those lookup functions as well. Eg

Code: Select all

   uint16_t EGT2_millivolts(uint16_t egt2_temperature){
    return (lookup_2d_linear(egt2_temperature, 
                            calibration.table.outputConversion.EGT2,
                            TABLE_EGT2_OUTPUT_CONVERSION_SIZE,
                            TABLE_EGT2_OUTPUT_CONVERSION_MIN,
                            TABLE_EGT2_OUTPUT_CONVERSION_MAX)
            ); 

[AngelMarc]

3d means X and Y for location, Z for value, so you have 3D tables. 2D means 1 row or column only and a value.

Sounds like redefining ordinary words to be less intuitive. I don't like it.

[pman92]

Sounds like redefining ordinary words to be less intuitive. I don't like it.

A 3D table visualises as a wavy 3D map with high and low areas.
A 2D table visualises as a line on a graph

[AngelMarc]

Sounds like redefining ordinary words to be less intuitive. I don't like it.

A 3D table visualises as a wavy 3D map with high and low areas.
A 2D table visualises as a line on a graph

I'm going to keep thinking in math terms where the result isn't a spatial dimension.

[AngelMarc]

That was a simple change. Do still need to test though.
But since part of the testing is changing values and comparing before and after, going to move on.

Code: Select all

void loop() {
  if (newSample) {
    newSample = false;

    // --- ADC rolling average (12-bit to 7-bit scale) ---
    total -= readings[bufIndex];
    int newVal = analogRead(A0);
    readings[bufIndex] = newVal;
    total += newVal;
    bufIndex = (bufIndex + 1) % 24;

    int avg12bit = total / 24;
    adcIndex = (avg12bit >> 5) - 1;  // () for simple order of opperation, minus 1 for avoiding index wrapping

    // --- Calculate RPM timing (µs per event) ---
    unsigned long RPMTime = pulseHighTime + pulseLowTime;
    RPMTime = constrain(RPMTime, 125, 125000);  // 20k RPM to 20 RPM

    RPMIndex = (uint8_t)(2500000/(RPMTime*600));

    // --- Update delay values from tables ---
    currentOnDelay11 = Dstart[RPMIndex][adcIndex];
    currentOffDelay11 = Dend[RPMIndex][adcIndex];

    currentOnDelay4 = Istart[RPMIndex][adcIndex];
    currentOffDelay4 = Iend[RPMIndex][adcIndex];
  }